A French foreign legion general must make a trip across the deserts of Tunis to a remote outpost. He must travel on foot from the nearest town, and the distance is such that it will take a person six days to cover it.
The problem is that a person on foot can only carry enough water and provisions to last him four days. The general can take with him any number of assistants to help him carry the supplies, but they must be fed as well, and cannot be left stranded in the desert.
How will the general make it across, and how many assistants will he need to help him? (Find the smallest number.)
On the first day, the general leaves with 4 days of supplies, and one assistant accomponies him with 3 days worth.
After 1 day, the general has 3 days worth, and the assistant has 2 days worth. The assistant gives the general 1 days worth. The general now has 4 days worth and the assistant has 1 day worth. The assistant goes home, the general presses on.
On day 4, the general has 1 day worth of supplies, but he is two days away from the outpost. On this day a second assistant leaves the outpost with 3 days worth of supplies.
After 1 day (day 5 of the total journey), the general meets up with the new assistant. At this point, the general has no supplies and the assistant has 2 day worth. The assistant gives the general 1 day of supplies. The general has 1 day, the assistant has 1 day. They both safely reach the outpost.
Total supplies used = 10 days worth.
General is busy all 6 days, but assistants were only needed for 2 days each.
More efficient answer
